UBC Theses and Dissertations
Activity and behaviour in spawning sockeye salmon Lake, Randal Gary
Total energy expenditures and muscle activity have been measured in spawning salmon but behaviour specific energy-use has never been been measured directly. This research used electromyogram (EMG) telemetry, combined with behaviour observations to assess activity levels and estimate relative energy use during spawning in sockeye salmon, Oncorhynchus nerka. My main objectives were to: assess the ability of EMG transmitter technology to discriminate between the rate of muscle activity during short duration specific behaviours and general activity, and; use these data to compare the total activity between spawning stages, sex, and year. EMG data were converted to rate of tail beats and, using synchronized clocks, were matched with specific spawning ground behaviours. Rate of tail beats, behaviour duration, and behaviour frequency were multiplied to estimate the total tail beats for the mean duration of male and female fish on the spawning grounds. Sequential reproductive stages were observed in the spawning stream. Males and females were given a 'status' designation corresponding to their reproductive stage. Behaviour specific analysis of total tail beats for each behaviour revealed that males and females of different reproductive status had different mean total tail beats for some behaviours. Total tail beats for males and females in two consecutive years revealed that females utilized more tail beats in one year and equal tail beats to the males in the other year. Total tail beats were strongly associated with duration of each fish in the spawning stream. This along with other observations suggests that the majority of energy expended on the spawning ground was due to non-specific general behaviours such as "holding position" (eg. behaviours not involved in act of spawning or defense/competition for spawning areas). EMG technology appears to be a highly effective tool for studying spawning ground activities in salmon.
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